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Hydraulic failure defines the recovery and point of death in water-stressed conifers


Brodribb, TJ and Cochard, H, Hydraulic failure defines the recovery and point of death in water-stressed conifers, Plant Physiology, 149, (January) pp. 575-584. ISSN 0032-0889 (2009) [Refereed Article]

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2009 American Society of Plant Biologists

DOI: doi:10.1104/pp.108.129783


This study combines existing hydraulic principles with recently developed methods for probing leaf hydraulic function to determine whether xylem physiology can explain the dynamic response of gas exchange both during drought and in the recovery phase after rewatering. Four conifer species from wet and dry forests were exposed to a range of water stresses by withholding water and then rewatering to observe the recovery process. During both phases midday transpiration and leaf water potential (Cleaf) were monitored. Stomatal responses to Cleaf were established for each species and these relationships used to evaluate whether the recovery of gas exchange after drought was limited by postembolism hydraulic repair in leaves. Furthermore, the timing of gas-exchange recovery was used to determine the maximum survivable water stress for each species and this index compared with data for both leaf and stem vulnerability to water-stress-induced dysfunction measured for each species. Recovery of gas exchange after water stress took between 1 and .100 d and during this period all species showed strong 1:1 conformity to a combined hydraulic-stomatal limitation model (r2 = 0.70 across all plants). Gas-exchange recovery time showed two distinct phases, a rapid overnight recovery in plants stressed to ,50% loss of leaf hydraulic conductance (Kleaf) and a highly Cleaf-dependent phase in plants stressed to .50% loss of Kleaf. Maximum recoverable water stress (Cmin) corresponded to a 95% loss of Kleaf. Thus, we conclude that xylem hydraulics represents a direct limit to the drought tolerance of these conifer species.

Item Details

Item Type:Refereed Article
Research Division:Biological Sciences
Research Group:Evolutionary biology
Research Field:Biological adaptation
Objective Division:Environmental Management
Objective Group:Terrestrial systems and management
Objective Field:Terrestrial biodiversity
UTAS Author:Brodribb, TJ (Professor Tim Brodribb)
ID Code:62113
Year Published:2009
Web of Science® Times Cited:527
Deposited By:Plant Science
Deposited On:2010-03-10
Last Modified:2010-05-10

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